1. Field of the Invention
This invention relates generally to orthodontic appliances and more particularly to devices for expanding the maxillary arch.
2. Prior Art
A number of orthodontic appliances have been developed over the years to shape and contour the teeth. These include devices to shape the maxillary arch for proper bite. A typical example of such devices in U.S. Pat. No. 3,618,214, invented by Armstrong, issued Nov. 9, 1971, entitled "Coiled Wire Spring Appliances for use in Orthodontics".
The purpose of these devices is to provide light continuous force in the appropriate direction to control growth of teeth. There are a number of problems associated with these appliances as they exist at the present time.
First, these devices often require multiple adjustments for effectiveness. They do not provide continuous even force but rather have a force which tends to diminish with use. Additionally, because of the numerous pieces used, they make proper hygiene extremely difficult. The numerous anchor pieces also have a tendency to cut into the teeth and gums with pain resulting. Finally, these devices are very visible in the mouth and are uncosmetic.